Global positioning system (GPS)-based navigational aids are well known. In their simplest form, they provide latitude and longitude information. GPS systems that have a greater degree of sophistication are able to translate the raw GPS coordinate data into useful information, such as the user's location with respect to landmarks or potential objectives (e.g., restaurants, automobile service stations). Although the majority of such products present information visually, navigational support systems that present the information by voice do exist. An example is the iGuidance navigation program. In this program, the voice notifications are generated by a device that is co-located with the user and that supports text-to-speech (TTS) conversion, such as a laptop PC. Hence, the device must be TTS-enabled in order for the voice notification to work. This is a significant expense that not everyone wishes to undergo. Moreover, many devices such as inexpensive cellular phones lack the processing power and memory required to support TTS.
GPS-equipped cellular telephones are readily available. It is possible for a centralized server to query these phones, asking them to echo back their GPS coordinates. Indeed, within the prior art, there are services in which a GPS-equipped user may place a cellular phone call to a centralized resource, request navigational assistance, and then receive the information by voice from a person who has access to the caller's GPS data. An example thereof is the “OnStar” service from General Motors Corp., in which the standard end-user configuration includes a cellular telephone and remotely-accessible GPS system. The voiced navigational support received by OnStar customers is from a person, who provides the ability to understand and respond to the unstructured spoken statements and queries of customers, some of which may be from people in emergency situations.
Visually impaired persons may find themselves in new surroundings where they do not know exactly where they are—for example, they may not know what street corner they are standing at. A non-impaired person can merely look around and either read the street signs or recognize the surroundings. But this simple solution is not available to the visually impaired. They must therefore rely on the kindness of passers-by to tell them where they are. The visually-impaired persons could undergo the expense of equipping themselves with TTS-enabled GPS-equipped devices. However, as noted above, this may be a significant and perhaps even a prohibitive expense.